For identifying of an astrophysical object as a
black hole, it is required to know the maximum gravitational mass
of a neutron star for stability against collapse into a black
hole. In the other word, it is expected that below a certain
maximum mass, degeneracy pressure due to the nucleons is
sufficient to prevent an object from becoming a black hole
[1]}. Therefore, determining the maximum gravitational
mass of neutron star is of special importance in astrophysics.
